Designing a Square Wave: The 74HC14 Oscillator Guide Building a basic square wave generator doesn't always require a 555 timer. The 74HC14 Hex Schmitt Trigger Inverter Go to product viewer dialog for this item.
When choosing values for your circuit, keep these practical limits in mind: Resistor ( Use values between Avoid values below 1k to prevent excessive current draw from the output pin. Capacitor ( 74hc14 oscillator calculator